The present invention relates to a melt spinning apparatus for producing a plurality of yarns.
In the production of yarns by melt spinning, one distinguishes between undyed, unicolored, and multicolored yarns, which require different spinning apparatus. In particular in the production of multicolored carpet yarns, apparatus are used, which extrude in one spinning position a plurality. of filament bundles and subsequently combine these filament bundles to a yarn. Such apparatus is described, for example, in EP 0485871 and corresponding U.S. Pat. No. 5,251,363. In the known apparatus, an extruder produces a corresponding melt flow for each color. For each color, the spinning position produces one filament bundle, with all filament bundles being combined to the multicolored yarn. Thus, a plurality of extruders are associated to the spinning position. In practice, a plurality of spinning positions are arranged side by side. In this arrangement, the melt flows of the extruders are distributed to the individual spinning positions by a plurality of distributor pumps. Depending on the design of the distributor pump, one distributor pump supplies a plurality of spinnerets at the same time. These spinnerets are associated respectively to one spinning position. Such spinning apparatus are thus laid out according to the number of the dyes used for the production of a multicolored yarn per spinning position.
However, in practice, it is desired to produce with such a spinning apparatus also unicolored yarns. Yet is it known, that unicolored yarns have a lower denier than multicolored yarns. Thus, the production of unicolored or undyed yarns with the known apparatus is possible only with a considerably lower output, or even impossible in the case of very low yarn deniers.
Furthermore, it is necessary that all spinning positions connected via the controlled melt flow system produce a yarn of the same color and kind. In particular, in the case of a dye change, high production losses are incurred, until all spinning positions connected to the controlled melt flow system are changed to the new dye.
It is therefore the object of the invention to further develop a spinning apparatus of the initially described kind such that it is possible to produce multicolored, unicolored, or undyed yarns with a substantially unchanged output. A further object of the invention is to provide an apparatus with a flexible control of the melt flow and yarn path adapted to the respectively produced yarn.
The above and other objects and advantages are achieved by the provision of a melt spinning apparatus and method which includes at least one extruder for producing a polymer melt flow, and at least two spinning positions arranged side by side and with each spinning position including at least one spinneret. Also, a distributor system is provided for delivering a portion of the melt flow to each spinneret of each spinning position and such that each spinning position extrudes a filament bundle composed of a plurality of strandlike filaments.
The spinnerets of adjacent spinning positions are arranged side by side in such a manner that at least one filament bundle of the one spinning position can be combined to a yarn with at least one filament bundle of the adjacent spinning position. The special advantage of this configuration lies in that it is possible to vary the number of the filament bundles that are combined to a yarn. Thus, there exists the possibility of combining in the production of a multicolored yarn a larger number of filament bundles to a yarn, and of combining in the production of a unicolored or an undyed yarn a lesser number of filament bundles or only one filament bundle. This permits producing with the same output both a multicolored yarn of a high denier and a unicolored yarn of a low denier. For example, in a spinning apparatus with two spinning positions, which comprise each three spinnerets, it is possible to selectively produce three yarns by combining respectively two adjacent filament bundles, or two yarns by combining three adjacent filament bundles. However, it is also possible to spin, without combining, each filament bundle to one yarn.
Each of the spinning positions comprises a plurality of serially aligned spinnerets and the spinnerets of adjacent spinning positions are serially aligned. This facilitates the production of a plurality of parallel side by side yarns at the same time.
To produce at least one yarn, which is formed by combining two filament bundles of adjacent spinning positions, it is desirable to have the spacing between a spinneret arranged at the edge of the one spinning position and an adjacent spinneret of the other spinning position be the same or insignificantly greater than the spacing between two adjacent spinnerets of one of the spinning positions. This ensures that the spacing between the spinnerets and the converging points of the yarns is the same for each yarn. With that, it is possible to use in like manner yarn guide arrangements of the spinning apparatus both in the production of multicolored yarns and in the production of unicolored yarns.
In the case that a plurality of filament bundles of adjacent spinning positions are combined to a yarn, it will be advantageous when the spacing between two spinnerets of adjacent spinning positions is made smaller than the spacing between the spinnerets of one of the spinning positions. Such a construction of the spinning apparatus makes it likewise possible to combine the filament bundles in several planes.
In one preferred embodiment, each of the spinning positions comprises a separate housing for three serially arranged spinnerets. In the production of multicolored yarns, each spinneret of a spinning position extrudes a filament bundle of a certain color, so that a three-colored yarn can be produced. In the production of unicolored or undyed yarns, the three spinnerets of a spinning position produce each a filament bundle of the same color. In this instance, three yarns are simultaneously produced in each pair of spinning positions. This embodiment is especially advantageous for producing BCF yarns in a corresponding further treatment of the yarns.
The distributor system includes a plurality of distributor pumps, and a valve unit may be provided which interconnects the extruders and the distributor pumps. The valve unit has a plurality of switching positions, which provides the advantage that in the production of a unicolored or an undyed yarn, one spinning position processes the melt of one extruder. With that, it is possible to produce yarns of a great uniformity in their composition.
In one of the switching positions of the valve unit, each spinning position is associated to one extruder. Thus, it is possible to operate the spinning positions in the spinning apparatus with differently dyed filament bundles for producing colored yarns. A special advantage of the invention lies in that the dye changes can be performed in the spinning position rapidly and without great production losses.
In the second switching position of the valve unit, each of the distributor pumps of a spinning position is associated to one of the extruders, so that the spinnerets of the spinning position extrude the polymer melts of a plurality of extruders. In this adjustment, it is advantageous to produce multicolored yarns.
Naturally, the valve unit could also be formed by a known stationary distributor block, which is exchanged for a second distributor block, when need arises. It would also be possible to construct the distributor block with a plurality of plates, so that one plate or a portion of the plates is made exchangeable for changing the melt flow.
A takeup device may be provided which has a plurality of winding positions for winding each of the yarns to a package. In this takeup device, the number of winding positions is greater than the number of the upstream spinning positions. This permits associating one winding position to each spinning position in the production of multicolored yarns. In this instance, the winding positions that are arranged between two adjacent spinning positions, remain inoperative. Only in the production of unicolored yarns, is one package wound in each winding position.
To combine the filament bundles, a yarn treatment device is proposed, which comprises a plurality of treatment stations. The number of the treatment stations is greater than the number of the upstream spinning positions. Thus, a change in the production processes will make is unnecessary to revamp the stations for producing the corresponding number of yarns. In the production of unicolored yarns, each treatment station treats one yarn.
Advantageously, the treatment stations are designed and constructed as texturing nozzles, so that it is possible to produce a crimped yarn.
However, it is also possible to combine the filament bundles within the treatment station by an entanglement nozzle. To produce a crimp in the yarn, the filament bundles are textured before they enter the entanglement nozzles.
The use of the apparatus according to the invention distinguishes itself by its great flexibility in the production of yarns. With the use of the apparatus, it has been accomplished to produce qualitatively superior yarns in a unicolored or multicolored version.